【作者】 赵宏；

【导师】 黄洪钟； 屈福政；

【作者基本信息】 大连理工大学 ， 机械设计及理论， 2008， 博士

【摘要】 来自市场的产品创新需求,在经过可分若干层次的设计阶段而投入生产、营销,并最终转化为现实产品的过程中,概念设计起着重要作用,对新产品的性能和市场竞争力具有决定性的影响。为此,对产品概念设计过程的相关理论、方法进行研究很有必要。国内外学术界在近二十年来对产品现代设计理论进行了大量研究,取得了许多成果,涵盖了设计需求的获取和表达、概念产品信息建模、概念设计过程建模、设计方案求解和评价等方面。本文综述了20世纪90年代中期至今与机械产品概念设计理论和方法相关的国内外文献,进行了较为细致的分类和研究;在此基础上,针对该领域尚未得到足够关注或尚未得到充分解决的若干重点和难点问题,提出了自己的观点和解决方法,并力求通过专用强夯机设计实例对所提方法的有效性、实用性进行验证,以期实现理论与实践的较完美结合。对应用于本文工作的基础理论工具进行了简要介绍,如模糊语言变量、矩阵的有向图、模糊图论、点态模糊交/并集运算等基础理论等。对影响概念产品之市场竞争力的两个关键问题进行了集中的探讨。首先针对概念产品的质量保证问题,提出以模糊语言变量作为质量需求信息建模工具,对变量的语言值及其对应的论域子集的适当选取动态地表现市场对概念产品质量需求的决定作用,论域子集所界定的参数值区间可直接作为概念设计的约束条件。随后,分析了机械产品创新过程中工作环境、市场需求等因素的变化对产品概念设计过程的决定性影响,在此基础上建立了环境—需求—功能—行为—结构(E-R-F-B-S)变量集映射动态模型,利用7种映射单元之间的有序组合归纳出4条产品创新链,为设计者在机械产品设计实践中的若干种创新思维过程建立了简明的框架模型。通过确立创新链与有向图、有向图与稀疏矩阵之间的对应关系,建立了创新链的数学模型,进而提出了创建以稀疏对称阵为输入变量的计算机辅助概念设计推理系统的构想。为使概念设计方案生成过程能直观、形象地表达,将模糊图论引入该过程,利用模糊与/或树表征产品概念空间。以对基本功能载体技术性能的模糊综合评判为基础,利用模糊设计理论中的最优水平值方法遴选基本功能载体,然后通过对功能载体的组合得到备择方案并进行综合评价,达到优化概念设计方案求解过程和提高设计效率的目的。对于概念产品可靠性预测这一方案评价中的重点问题,利用故障树分析方法,将故障树底事件发生可能性的模糊语言描述量化为模糊集的元素。在故障树分析中,由于现有的变参数点态模糊集运算模型存在缺陷,将用于点态模糊交集运算的参数型Schweizer(3)算子、点态模糊并集运算的参数型Hamacher算子分别选作概念产品故障树中“与”、“或”事件可能性量化预测的工具,并依据专家经验为以上算子分别选定了表征最乐观、最保守预测的2个参数极值,从而为设计者视具体使用环境来进行概念产品可靠性预测提供了必要的参照。作为一种应用渐广的地基处理机械,强夯机经历了由履带式起重机改装的“代用强夯机”到专用强夯机的发展历程。专用强夯机的开发针对特定的工作环境,体现了全新的概念,其概念设计过程对机械产品概念设计具有典型性。本文以QH800型专用强夯机概念设计为例,通过对该型号强夯机的主要结构、各子系统的设计,及对强夯机的2种液压主回路和3种控制系统的可靠性预测,着重说明创新链方法、故障树分析结合参数化点态模糊集运算法在机械产品概念设计中的应用价值。更多还原

【Abstract】 A conceptual product, originating in the innovation requirement from the market, generally first goes through the multi-stage design process, then the manufacture and marketing stage, finally turns into reality. In this phase, conceptual design plays a key role, having critical influence on the overall performance and market competitiveness of the new product. Thus it is necessary to make research and investigation into the theories and methods relating to the issues with product conceptual design. From the researches on modern product design theory by the Academia at home and abroad in the last two decades, derived an amount of academic achievements concerning the essential points in process of conceptual design, ranging from the information gathering and managing of design requirements, product information modeling in conceptual design, conceptual design process modeling, to the generation and evaluation of conceptual product schemes. In this document, the literatures relating to the theories, ways and means of approaching conceptual design of mechanical products, at home and abroad since the mid 1990s in 20th century by now, have been collected, seriously sorted and studied; on this basis, to some key points and issues in conceptual design, which have not yet either been paid enough attention to or been fully settled, certain original viewpoints and methods are suggested. Design case study about special-used dynamic compaction machinery is done to exemplify the effectiveness and practicability of the suggested methods, aiming at combining this research work with engineering practice to a satisfying degree.The theoretical tools applied in this dissertation are introduced, including the fuzzy linguistic varible, sparse matrix corresponding to directed graph, fuzzy graph theory, and the pointwise fuzzy set-theoretic operations.Two key issues influencing the market competitive power of a conceptual product are studied intensively. Firstly, for the issue of quality assurance, this paper introduces a quality needs information modeling method, featured by the application of fuzzy linguistic variables. The decisive influence of the market conditions on the conceptual product quality needs can be dynamically represented through the properly-chosen fuzzy linguistic phrase and its corresponding quantitive parameter-value interval, which can be directly taken as constraints for conceptual design. Then, it is discussed that as for a conceptual mechanical product under innovation, the changes concerning its working environment and the varying market requirements have critical impact on the conceptual design process. Characterizing this kind of innovation process, a dynamic model of Environment-Requirement-Function-Behaviour-Structure (E-R-F-B-S) is put forward, which is featured by a series of mappings between the five kinds of variable sets. Named innovation chains, four kinds of innovation patterns depicting the designers’ usual trains of creative thoughts in the mechanical product design activities are outlined, represented by the ordered combinations of the seven mapping units in the E-R-F-B-S model. The mathematical model of innovation chain is established by determining the correspondence between innovation chain and directed graph, then directed graph and sparse matrix, thus making it possible to suggest the set up of a computer-aided reasoning system for conceptual design, sparse matrices as its input variables.To fercilitate the visualization of the scheme generation process in conceptual design, the fuzzy graph theory is introduced and the concept space is represented as a fuzzy AND/OR tree. On the basis of the fuzzy comprehensive technical performance evaluation of the fundamental function carriers, the method with respect to optimal-level-value in fuzzy set-theory is used to select the appropriate carriers; then through the carrier combination, the candidate schemes can be generated and comprehensively evaluated. Thus, the scheme solving process in conceptual design can be optimized and the design efficiency improved.As a key issue in design evaluation, the conceptual product reliability estimate can be made by means of Fault Tree Analysis (FTA), with a fuzzy set defined on the unit interval whose elements correspond with the fuzzy linguistic expressions of the basic events’ possibilities. The existing parameter-varying pointwise fuzzy set-theoretic operation model for FTA has obvious shortcoming, so the parameterized Schweizer(3) t-norm and parameterized Hamacher t-conorm are chosen, respectively as the means for the reliability estimate of AND/OR events. Respectively for the chosen parameterized t-norm and t-conorm, two parameter extrema are fixed refering to expert experience, to be used for making the most optimistic and the most pessimistic estimate, thus providing the necessary and reasonable reference for the designer to estimate a conceptual product’s reliability according to its working environment-to-be.With broad prospect of application in ground foundation construction, dynamic compaction machinery has undergone the development from so-called "substitute machinery" to the special-used kind. As a new concept being explored, the special-used machinery is characterized by specific working environment, and its conceptual design can be taken as a representative as for mechanical products. Conceptual design of the type QH800 of special-used machinery is discussed here. Through the elaboration of innovative design of the main assemblies and sub-systems, followed by the reliability estimates of two kinds of main hydraulic circuit as well as three kinds of circuit control system, the application significance of Innovation Chain and FTA coupled with parameterized pointwise fuzzy set-theoretic operations can be validated in mechanical products’ conceptual design.更多还原